Chemistry of hydrocarbon compounds – Unsaturated compound synthesis – By addition of entire unsaturated molecules – e.g.,...
Reexamination Certificate
2001-02-19
2002-08-13
Wood, Elizabeth D. (Department: 1755)
Chemistry of hydrocarbon compounds
Unsaturated compound synthesis
By addition of entire unsaturated molecules, e.g.,...
C585S506000, C585S509000, C502S102000, C502S152000, C502S153000, C502S154000, C502S155000, C502S158000, C502S162000, C526S090000, C526S095000, C526S100000, C526S126000, C526S127000, C526S128000, C526S135000, C526S136000, C526S142000, C526S143000, C526S144000, C526S171000, C526S183000, C526S193000, C526S233000, C526S237000
Reexamination Certificate
active
06433237
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an iron-based catalyst composition for producing oligomers of conjugated dienes.
BACKGROUND OF THE INVENTION
Conjugated dienes such as 1,3-butadiene and isoprene undergo a variety of catalytic oligomerization reactions to give cyclic or acyclic oligomers. These oligomers are valuable feedstocks for producing fine organic chemicals. For example, the dimers and trimers are utilized as intermediates for synthesizing plasticizers, flame retardants, terpenoid and sesquiterpenoid compounds of biological interest, and fragrances.
Various coordination catalyst systems based on nickel, palladium, cobalt, titanium, chromium, and iron have been reported for catalyzing the oligomerization of conjugated dienes. The majority of these catalyst systems, however, have no practical utility. because they have low activity and poor selectivity. The resulting oligomerization product is often a complicated mixture of cyclic and acyclic dimers, trimers, tetramers, and higher oligomers. Furthermore, some oligomerization catalyst systems also generate a certain amount of polymer in the oligomerization product mixtures.
Several iron-based coordination catalyst systems for oligomerizing conjugated dienes are known. For example, one process for the oligomerization of 1,3-butadiene employs a catalyst system comprising iron(III) acetylacetonate and triethylaluminum. Another process employs a catalyst system comprising iron(III) acetylacetonate, triethylaluminum, and triphenylphosphine. Yet another process employs a catalyst system comprising iron(III) chloride, triphenylphosphine, and triethylaluminum. All of these iron-based catalyst systems, however, have very low activity and poor selectivity, and the resulting oligomerization product is a mixture of cyclic and acyclic dimers, trimers, and higher oligomers, as well as polymer.
Because the oligomers of conjugated dienes are useful products and the catalyst systems known heretofore have many shortcomings, it would be advantageous to develop a new catalyst system that has high activity and selectivity for preparing oligomers of conjugated dienes.
SUMMARY OF THE INVENTION
In general the present invention provides a catalyst composition that is the combination of or the reaction product of ingredients comprising (a) (i) a halogen-containing iron compound or (ii) an iron-containing compound and a halogen-containing compound, (b) a silyl phosphonate, and (c) an organoaluminum compound.
The present invention also includes a catalyst composition formed by a process comprising the steps of combining (a) (i) a halogen-containing iron compound or (ii) an iron-containing compound and a halogen-containing compound, (b) a silyl phosphonate, and (c) an organoaluminum compound.
The present invention further includes a process for forming conjugated diene oligomers comprising the step of oligomerizing conjugated diene monomers in the presence of a catalytically effective amount of a catalyst composition formed by combining (a) (i) a halogen-containing iron compound or (ii) an iron-containing compound and a halogen-containing compound, (b) a silyl phosphonate, and (c) an organoaluminum compound.
Advantageously, the catalyst composition of this invention has very high activity, which allows conjugated diene oligomers to be produced in very high yields with low catalyst levels after relatively short oligomerization times. In addition, since this catalyst composition is highly active even at low temperatures, the oligomerization may be carried out under very mild temperature conditions, thereby avoiding thermal polymerization and/or cracking or other deleterious effects. Further, the iron compounds that are utilized are generally stable, inexpensive, relatively innocuous, and readily available. Furthermore, this catalyst composition is very selective. For instance, by utilizing this catalyst, 1,3-butadiene can be converted quantitatively to acyclic dimers without the production of any other products.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
The catalyst composition is formed by combining (a) (i) a halogen-containing iron compound or (ii) an iron-containing compound and a halogen-containing compound, (b) a silyl phosphonate, and (c) an organoaluminum compound. In addition to these catalyst ingredients (a), (b), and (c), other organometallic compounds or Lewis bases that are known in the art can also be added, if desired.
In one embodiment, where a halogen-containing iron compound is used as ingredient (a), various halogen-containing iron compounds or mixtures thereof can be employed. The iron atom in the halogen-containing iron compounds can be in various oxidation states including, but not limited to, the +2, +3, and +4 oxidation states. Divalent iron compounds (also called ferrous compounds), where the iron atom is in the +2 oxidation state, and trivalent iron compounds (also called ferric compounds), where the iron atom is in the +3 oxidation state, are preferred.
Suitable halogen-containing iron compounds that can be utilized include, but are not limited to, iron fluorides, iron chlorides, iron bromides, iron iodides, iron oxyhalides, and mixtures thereof. Some specific examples of halogen-containing iron compounds include iron(II) fluoride, iron(III) fluoride, iron(III) oxyfluoride, iron(II) chloride, iron(III) chloride, iron(III) oxychloride, iron(II) bromide, iron(III) bromide, iron (III) oxybromide, and iron(II) iodide.
In a second embodiment, where an iron-containing compound and a halide-containing compound are used as ingredient (a), various iron-containing compounds or mixtures thereof can be employed.
Preferably, iron-containing compounds that are soluble in a hydrocarbon solvent such as aromatic hydrocarbons, aliphatic hydrocarbons, or cycloaliphatic hydrocarbons are employed. Hydrocarbon-insoluble iron-containing compounds, however, can be suspended in the oligomerization medium to form the catalytically active species and are therefore useful.
The iron atom in the iron-containing compounds can be in various oxidation states including, but not limited to, the 0, +2, +3, and +4 oxidation states. Divalent iron compounds and trivalent iron compounds are preferred. Suitable iron-containing compounds that can be utilized include, but are not limited to, iron carboxylates, iron organophosphates, iron organophosphonates, iron organophosphinates, iron carbamates, iron dithiocarbamates, iron xanthates, iron &bgr;-diketonates, iron alkoxides or aryloxides, organoiron compounds, and mixtures thereof.
Suitable iron carboxylates include iron(II) formate, iron(III) formate, iron(II) acetate, iron(III) acetate, iron(II) acrylate, iron(III) acrylate, iron(II) methacrylate, iron(III) methacrylate, iron(II) valerate, iron(III) valerate, iron(II) gluconate, iron(III) gluconate, iron(II) citrate, iron(III) citrate, iron(II) fumarate, iron(III) fumarate, iron(II) lactate, iron(III) lactate, iron(II) maleate, iron(III) maleate, iron(II) oxalate, iron(III) oxalate, iron(II) 2-ethylhexanoate, iron(III) 2-ethylhexanoate, iron(II) neodecanoate, iron(III) neodecanoate, iron(II) naphthenate, iron(III) naphthenate, iron(II) stearate, iron(III) stearate, iron(II) oleate, iron(III) oleate, iron(II) benzoate, iron(III) benzoate, iron(II) picolinate, and iron(III) picolinate.
Suitable iron organophosphates include iron(II) dibutyl phosphate, iron(III) dibutyl phosphate, iron(II) dipentyl phosphate, iron(III) dipentyl phosphate, iron(II) dihexyl phosphate, iron(III) dihexyl phosphate, iron(II) diheptyl phosphate, iron (III) diheptyl phosphate, iron (II) dioctyl phosphate, iron(III) dioctyl phosphate, iron(II) bis(1-methylheptyl) phosphate, iron(III) bis(1-methylheptyl) phosphate, iron(II) bis(2-ethylhexyl) phosphate, iron(III) bis(2-ethylhexyl) phosphate, iron(II) didecyl phosphate, iron(III) didecyl phosphate, iron(II) didodecyl phosphate, iron (III) didodecyl phosphate, iron(II) dioctadecyl phosphate, iron(III) dioctadecyl phosphate, iron(II) dioleyl phosphate, iron(III) dioleyl phosphate, iron(I
Bridgestone Corporation
Burleson David G.
Reginelli Arthur M.
Wood Elizabeth D.
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